Let the lessons in this chapter take you on a virtual tour of galaxies, groups of dust, gas and stars that rely upon gravity to keep them together. In this chapter, our knowledgeable and experienced instructors will use short, fun-to-watch videos, online self-assessments and lesson transcripts to teach you about the different types of galaxies, including their distinguishing features and parts. Rewatch the videos as often as you wish to make sure that you understand the presentations, then use the handy quizzes to test your own knowledge of astronomy and galaxies. If you find yourself stuck on a particular topic, you can even post a question to the instructor!

In this chapter, you'll learn:

How the Hubble Tuning Fork is used to classify galaxies

How to measure galaxies

How stars move around in galaxies

How matter is recycled in the Milky Way

How black holes are formed

Video

Objective

Links in the Distance Chain

Describe the components of the distance chain, including supernovae.

The Distribution of Galaxy Properties Along the Hubble Tuning Fork

Describe the characteristics of galaxies within the context of the Hubble Tuning Fork.

Summary:

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